Molecular oxygen (o2), which is required for the production of atp by mitochondria, must pass through at least three membranes to get to the enzymes where it is used. o2 is also produced in chloroplasts and must pass through at least four membranes to be released from the plant. how does o2 move across biological membranes? a. there are numerous protein transporters that allow o2 to travel across membranes. b. o2 is nonpolar, and very small, so it can diffuse across the membrane. c. o2 undergoes a chemical reaction that binds it to other substances that are transported across the membranes. d. o2 is hydrophilic and travels with water across the membranes.

O2 is nonpolar, and very small, so it can diffuse across the membrane. (Ans. B)

Explanation:

Cell membrane which is also known as biological membrane that helping in the separation interior of the all cell from the outside environment or extracellular space.

Cell membrane is selective permeable in nature and able to regulate what exist and enter the cell. It's helping in facilitating the transport of material which is needed for survival. The movement of substances across the membrane can be two types active or passive.

Passive transport doesn't require cellular energy, and it includes osmosis and diffusion. Some substances such as small molecules and ions like CO2 and O2 can move across the plasma membrane through the diffusion which is including in passive transport.